The polypeptide backbone of recombinant human zona pellucida glycoprotein-3 initiates acrosomal exocytosis in human spermatozoa in vitro.
Human gamete interaction is of fundamental biological importance, yet the molecular interactions between spermatozoa and the zona pellucida are poorly understood. Surprisingly, the role of the polypeptide backbone of zona pellucida glycoprotein 3 (ZP3), the putative ligand for spermatozoa activation, has been largely overlooked. Purified recombinant human ZP3 was expressed in Escherichia coli as a C-terminal fusion to the dimeric glutathione S-transferase (GST) from Schistosoma japonicum and was shown to induce acrosomal exocytosis in live, capacitated human spermatozoa. The level of exocytosis is comparable with that obtained using purified, glycosylated, recombinant human ZP3 [van Duin, M., Polman, J.E.M., DeBreet, I.T.M., Van Ginneken, K., Bunschoten, H., Grootenhuis, A., Brindle, J. and Aitken, R.J. (1994). Biol Reprod. 51, 607-617]. These data imply that the polypeptide chain of human ZP3 contributes to recognition of spermatozoa during acrosomal exocytosis in vitro.
Chapman
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Krebs Institute, Department of Molecular Biology and Biotechnology, University of Sheffield, P.O. Box 594, Firth Court, Western Bank, Sheffield S10 2UH, U.K.
Kessopoulou
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Andrews
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Hornby
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Barratt
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D000177:Acrosome / Q000502:physiology*; D015153:Blotting, Western; D004527:Egg Proteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification; D004591:Electrophoresis, Polyacrylamide Gel; D005089:Exocytosis; D005982:Glutathione Transferase / Q000235:genetics / Q000378:metabolism; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis* / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000502:physiology*; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D015044:Zona Pellucida / Q000737:chemistry / Q000502:physiology*; D000072216:Zona Pellucida Glycoproteins
D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; C000606517:ZP3 protein, human; D000072216:Zona Pellucida Glycoproteins; D005982:Glutathione Transferase